Men in Black (also called MIBs) are alleged to visit individuals who have witnessed a UFO and warn them not to tell others about what they have seen. Men in Black supposedly use all forms of persuasion to silence UFO witness-including the threat of deadly force if necessary. These Men in Black are usually seen in groups of three and are thought to be either extra terrestrial enforcers or government intelligence agents. Men in Black are responsible for silencing witnesses to UFOs and ensuring that UFO events are kept hidden from the public.

Men in Black pose as salesmen, utility repairmen or agents of the government to gain access to UFO witnesses. They harass UFO witnesses through phone calls and surprise visits. Men in Black are alleged to drive black vintage Buicks or Lincoln town cars.

What I don't understand is, assuming for the sake of argument that they're real, why don't these MIB offer incentives for keeping quiet instead of harassing alleged UFO witnesses and generally getting on their bad side? You can achieve more with honey than with vinegar. Regardless if the MIB are government spooks or alien agents, they'll have sufficient resources to handsomely reward people for their silence.

@ausador: The concept of MIB has been around a lot longer than the films. I remember having a UFO book as a child that discussed them.

What I don't understand is this. Let's pretend there is some evidence for the Men in Black. What piece of evidence would point out to "either" one or another so vastly different things as the government or aliens. How can you look at, say, a picture, look at me and say: "You know Seeker, I'm not sure. This is either a government agent or an alien life form" ?